An expert advisory committee has been quietly scrapped after it warned the future safety of Britain's ageing nuclear plants was being put at risk by poor performance, delays and budget cuts.

The Nuclear Safety Advisory Committee (NuSAC), which has been offering critical advice to Britain's health and safety watchdog for nearly 50 years, was disbanded without any public announcement.

Former members of NuSAC are now worried about the lack of independent safety advice at a time when the government is embarking on a major expansion and clean-up of nuclear power.

Some former members privately suspect that NuSAC was shut down in October because it could have hampered government plans for a new programme of nuclear reactors. "This was just the time to get rid of a potential pest and spanner in the works of the brave new world of nuclear regulation and build," said one.

Some of NuSAC's recent criticisms — particularly on potential shortfalls in the future funding of nuclear decommissioning and radioactive waste management — were forthright. "Maybe that was enough to rock the boat," added the former NuSAC member.

Some committee members are also angry at suddenly being told in September that their next meeting was cancelled. "The way we were treated was shabby, to be honest," said another former NuSAC member.

NuSAC consisted of 19 safety experts, including scientists, academics, trade unionists and business executives, none of whom were paid. It reported to the Health and Safety Executive (HSE) and was chaired for the past four years by Dr Stephen Vranch, a chemical engineer from Jacobs Engineering.

"We are anxious to ensure that a successor body to NuSAC is set up as soon as possible," he said. "It is essential that nuclear safety regulators continue to receive good, independent advice, particularly at a time of great change in the nuclear industry."

NuSAC had been "passionate" about safety and spoke with "tremendous authority", Vranch argued. "I believe we did good work and raised important concerns on the future funding of nuclear decommissioning and waste management, on skills shortages, on the siting of new nuclear power stations and on other issues."

NuSAC's demise followed the launch of a major review of nuclear regulatory arrangements by the government's nuclear adviser, economist Dr Tim Stone. In a report last month, he recommended more staff and a major shake-up for the HSE, but made no mention of an advisory committee.

Marion Hill, a radiation scientist and former NuSAC member, thought it was unclear why the committee had not been allowed to carry on until a replacement could be set up. "It is a very busy time for the nuclear industry and I would have thought that HSE needed access to independent safety advice," she said.

The absence of NuSAC made it more difficult to find out about the regulation of nuclear plants. She argued: "Without NuSAC there is less information in the public domain about nuclear safety."

In an unpublicised report last July, NuSAC warned that programmes to deal with radioactive wastes from decommissioning the Sellafield nuclear complex in Cumbria and other old nuclear plants had suffered "substantial slippages".

The slippages were caused by the "poor performance" of nuclear plants, delays in developing waste processing and budget restrictions, the report concluded. "There remains a lack of confidence that the high hazards are being tackled to a robust programme."

NuSAC has also expressed concerns about the likely impact on safety of the shortage of skilled staff. And it has identified shortfalls in the siting criteria for new nuclear stations.

But the HSE denied that NuSAC had been shut down because it raised inconvenient issues. According to an HSE spokeswoman, it was because of the review by Tim Stone. "The HSE board decided to defer on reconstitution of this committee until it knows what sort of advisory body will be best suited to the changing circumstances in the nuclear field," she said. "It will be reconstituted in some form in due course."

The spokeswoman claimed that HSE nuclear inspectors had access to independent advice on nuclear safety from other sources. And she promised that information on nuclear regulation would continue to be published.

Some nuclear industry experts argued that NuSAC was a relatively ineffectual committee that had failed to live up to what had been expected of it. But they too expressed grave concern that there was no immediate successor to the organisation at such a vital time, when nuclear newbuild and waste issues were high on the public agenda.